Several medical procedures involve deploying multiple sensors on the human body for the recording and monitoring of data required for patient care. Information, such as vital health parameters, cardiac activity, bio-chemical activity, electrical activity in the brain, gastric activity and physiological data, is usually recorded through on-body or implanted sensors/electrodes which are controlled through a wired or wireless link. Typical patient monitoring systems comprise a control unit connected through a wire to one or more electrodes coupled to the specific body parts of the patient. In some applications, such as with pulse oximeter or EKG (electrocardiograph) devices, the electrodes coupled to the body are easily managed as there are not too many (fewer number of electrodes). However, with applications that require a large number of electrodes to be coupled to the human body, the overall set up, placement and management of electrodes is a cumbersome process.
Neuromonitoring is the use of electrophysiological methods, such as electroencephalography (EEG), electromyography (EMG), and evoked potentials, to monitor the functional integrity of certain neural structures (e.g., nerves, spinal cord and parts of the brain) during surgery. The purpose of neuromonitoring is to reduce the risk to the patient of iatrogenic damage to the nervous system, and/or to provide functional guidance to the surgeon and anesthesiologist. Generally, neuromonitoring procedures such as EEG involve a large number of electrodes coupled to the human body. In an EEG procedure, the electrodes are used to record and monitor the electrical activity corresponding to various parts of the brain for detection and treatment of various ailments such as epilepsy, sleep disorders and coma. EEG procedures are either non-invasive or invasive. In non-invasive EEG, a number of electrodes are deployed on the human scalp for recording electrical activity in portions of the underlying brain. In invasive EEG, through surgical intervention, the electrodes are placed directly over sections of the brain, in the form of a strip or grid, or are positioned in the deeper areas of the brain. Each of these electrodes is coupled to a wire lead which, in turn, is connected to a control unit adapted to receive and transmit electrical signals. The electrical activity pattern captured by various electrodes is analyzed using standard algorithms to localize or spot the portion of brain which is responsible for causing the specific ailment.
The number of electrodes in EEG systems typically varies between 21 and 256. Increasing the number of electrodes in EEG procedures helps decrease the localization error and thus more ably assist the physician to better plan for surgical procedures. Accordingly, advanced EEG systems involve a high density electrode configuration with up to 256 electrodes for separately mapping the electrical activity corresponding to every portion of the brain. However, the overall set up and verification process becomes more time consuming and error prone as the number of electrodes increases in the EEG procedures.
In neuromonitoring, as each electrode is positioned at a different location to capture the electrical activity in its vicinity, the input recorded from each electrode has to be processed independently. The system is required to recognize the identity of each electrode and accordingly process the input received from that electrode. To achieve this, it is important that each electrode is coupled to the correct input channel in the control unit of the neuromonitoring system. However, in practical scenarios, it is possible that, while connecting a large number of electrodes to respective input channels, the medical care provider connects an electrode to a wrong input channel. This could result in making the entire process faulty. Therefore, in high density electrode configurations, the set up process is time consuming as the connection corresponding to each electrode needs to be separately established and then verified for integrity before starting the procedure. In practice, the time required to set up and verify large numbers of connecting leads prevents following the best practice of checking all electrodes and verifying their integrity before starting the procedure and hence compromises the quality of medical care.
Surgical applications in EEG also use grid electrodes which inherently combine multiple leads (up to 16) into a single connector, which is then attached to an adapter with 16 individual leads, and then to an amplifier that has inputs for each individual channel. However, when a patient is monitored with an EEG system having 200+ electrodes, even grouping these electrodes results in more than a dozen adapters and the connections corresponding to these adapters needs to be individually verified every time before starting a procedure.
Therefore, the current neuromonitoring medical devices involving a large number of electrodes do not provide an easy and convenient way for physicians to deploy such systems. These systems suffer from significant risk of unreliable measurements due to incorrect connections. There is significant risk of error in deploying such systems. Further, deployment of such systems is time consuming which prevents following the best practices and therefore compromises the quality of medical care.
Devices and systems are required which are convenient to use and do not consume too much time for deployment. Such devices and systems should automatically recognize the position or identity of various electrodes and associate the electrodes with a specific input channel, thereby not requiring the physician to manually map each electrode with a specific input channel.